Connecting to Your World

1. Connecting to Your World

2. Climates do change 1. Some changes take place naturally over many years, such as the build of ice during the ice age 2. Scientists have noticed rapid climate change that some believe is the result of human activity

3. Global Warming • Global warming and desertification are two possible threats to the environment • Global warming is an increase in the average temperature of the Earth’s atmosphere 1. Causes changes in the Earth’s overall climate 2. Earth’s average temperature has risen between 0.9 and i.3 degrees F since the late 1800s 3. Scientist believe that the warming is part of the larger cycle of warm and cold periods in the Earth’s history 4.Scientists also suspect that it is caused by humans

4. The Greenhouse Effect • The trapping of the sun’s heat by gases in the Earth’s atmosphere is the greenhouse effect 1. Gases act like the glass roof of a greenhouse 2. They let in solar energy which heats up the plant, but they trap much of the heat that rises from the Earth’s surface • Some greenhouse effect is necessary; without it you would be living on a freezing cold planet; the temperature would be about zero degrees Fahrenheit • Gases in the atmosphere that contributes to the greenhouse effect is called greenhouse gas • Greenhouse gases include water vapor and carbon dioxide, a gas composed of carbon and oxygen • Burning of fossil fuels such as coal, oil, natural gas, has caused an increase in carbon dioxide in the atmosphere • As this gas builds in the atmosphere, the atmosphere becomes warmer and speeds up the heating effect

5. The Impact on the Climate • Warmer temperatures could cause the ice caps and glaciers around the world to melt and sea levels to rise • Flooding could occur along coastal regions • Global- land use patterns would change • Some crops would no longer grow in certain areas • Some areas would be hotter and drier, with extreme heat, waves, droughts, forest fires • These changes would alter the fragile relationships between living things and the environment

6. Solutions • Lowering the levels of greenhouse gases is a complex, worldwide goal • Some nations generate huge amounts of greenhouse gases; these gases not only affect the nation but the whole world • To reduce greenhouse gases one solution might be to build more energy-efficient cars and factories • Another is to use alternate energy sources such as energy produced by the sun, or internal heat of the Earth • Cut emissions of carbon dioxide and other greenhouse gases • Emissions are substances discharged into the air

7. Desertification • Desertification is the process in which farmland becomes less productive because the land is degraded 1. Land becomes more desert-like, dry and unproductive 2. Desertification is a serious problem because it turns arid and semiarid areas into nonproductive wasteland 3. Desertification happens in Africa, China, the American West

8. Causes and Effects • In desertification, natural vegetation is removed and destroyed; soil is exposed to wind • Without shade from the sun, moisture in the soil evaporates more quickly 1. Dry top layers of soil particles blow away; soil becomes less able to support plant life • Practices of desertification are: • Overgrazing allowing animals to graze so much that plants are unable to grow back • Cultivation of marginal land planting crops on fragile soil • Deforestation cutting down trees and not planting new trees

9. Solutions • Build sand fences that interrupt the wind, or to use straw mats to reduce evaporation so young plants can take root • Use solar ovens in place of open fires that require wood • Planting trees fences and grass belts also reduce the spread of sandy areas • These practices are used in China and Africa • These are called sustainable practices • Sustainable practices use natural resources in such a way to ensure tat they exist for future generations 1. Work with the environment to protect the land, preserve wildlife, and repair the damage that has been done to the land 2. Allow people to live a better life and ensure that resources will be available both now and in the future

10. Questions Environmental Challenges • What is deforestation? • Why is desertification a serious problem? • What do some scientist believe is the cause of rapid climate change? • What could occur if the temperatures continue to get warmer? • What are the effects of desertification? • In what areas does desertification occur? • What are two possible threats to the environment • What is the greenhouse effect? • What is global warming? • What does emissions mean?